Alternative way to get Higher voltage other than A Charge Pump

[maiko]

Im thinking about a submini tube amp project and was considering the murder1 but using 12ax7 12au7 as tubes.
saw several youtube videos about and inverter using a 2sc5200 transistor. there are several of these videos on youtube
but i tried it and all i get it a buzzing sound.   

i followed the circuit as described the stuff i did different is the powersource which is a 12v 2amp  powersupply that
came off a PC monitor.    i tried to measure but im barely getting 30v AC and its constantly changing.


https://www.youtube.com/watch?v=uEwlxqxYB8Y

[Digital Larry]

Impossible to tell what is going on without a schematic, really.

[Rob Strand]

Old school self-oscillating inverter.   Very bulky with an iron core.
It's possible to get them to work on ferrite cores as well.
Frequency is pot luck without designing Tx from scratch.

http://www.repairfaq.org/sam/samschem.htm#schinv

[maiko]

Old school self-oscillating inverter.   Very bulky with an iron core.
It's possible to get them to work on ferrite cores as well.
Frequency is pot luck without designing Tx from scratch.

http://www.repairfaq.org/sam/samschem.htm#schinv

Thanks for that sir.   Im probably gonna try it again.    So i tested my transistors and found out they were busted
no reading what so ever from base (P)  to either collector (n) or Emitter (n).   
when i initially did this i had to load on the ac hi voltage side.   just my meter was hooked up could that have been
the reason my initial try failed?

[Rob Strand]

just my meter was hooked up could that have been
the reason my initial try failed?

The problem with all self-oscillating inverters is they usually have to drive the transformer core into saturation.
In many cases that can mean the current needs to reach a very high level.

Another possibility is too much current was driven into the base.

I built a lot of those inverters as a kid using all sorts of random transformers.    I blew-up transistors as well.

You can also build two transistor version,
https://en.wikipedia.org/wiki/Royer_oscillator

However the results also depend on the transformers.

[bushidov]

I've built a 12AX7 pre-amp using a 12V-18V wall-wart power supply going into a boost supply circuit. See below for schematic:


Works pretty good. If I use a 12V supply, I don't need to populate the U2 portion of the circuit on my PCB as I just jump the 12V directly to the pin 5 of the 12AX7 heater pin, but if I have a higher voltage wall-wart, then I need to step that down.

The circuit is based around the XL6007E1 switcher, which in this configuration will boost up to around 50V when driving a single tube. Just make sure the C9 - C20 caps are rated for 63V or more and that R11 and R13 are 1W resistors and you should be fine.

Basically, I robbed this circuit out of a Joyo Bantamp's preamp section. Sure, they used all surface mount components, but I was able to translate all but one to through-hole (the XL6007 is an 8-pin SOIC, but that one isn't too bad to solder).

[amz-fx]

Search for Nixie on this forum and you will find a verified power supply that uses a 555 chip that can boost the voltage high enough to power a tube.

regards, Jack